WS2801 Breakout

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WS2801 Breakout

Description:Replacement:BOB-11820. The new rev of this breakout now comes standard with the addressable WS2812 LED installed, go check it out! This page is for reference only.

This is a breakout board for the WS2801 RGB LED controller, the same IC used in our addressable RGB LED strips. The board comes with the chip on one side and an RGB LED on the other. Several of these breakouts can be chained together to form a display or an addressable string. Voltage, ground, clock and data are broken out as input on one side and output on the other to standard 0.1" spaced headers.

Yes, but keep in mind that these have a fairly high current draw, so if you add more than one you can quickly reach the maximum current draw allowed from your USB port. Check out some of the other comments here :)

Got two of these, just fantastic. Even on low settings they are bright. Being able to just set the colour using RGB values is cool. The only thing I cannot find, I would like to document and blog what I am doing, using Fritzing to show the layout of the breadboard and Arduino. I cannot find the part in any of the libraries or anywhere on the net. Is there a ready made part to use in Fritzing?

The ws2801 datasheet shows resistors on the output and the feedback pins. Your circuit does not have them, so would I just use the appropriate resistors for the led on the feed back pins and connect the led directly? (I’m talking using the bare chip, not your breakout)

With the strips I thought I had damaged a couple I was playing with and the library suggested by Sparkfun did not explain itself very well . I had difficulty understanding it. In the first post here is a link to a page on the strip and its suggested library is http://www.bliptronics.com/%5Carduinocode%5Cblip_leds_spi_2801.zip

I got this library and it required three changes -Change WProgram.h to Arduino.h and delete the reference to wiring.h. With these changes it now runs on Arduino Version 1 and I noticed the reference text included with the library had some good explanation notes for novices like myself.

Update.
I managed to get the code working.
I used a tiny85 and if anyone is interested I can send them the code or post it where they wish.
Works but is crude.
The arduino code was bit banging it out. Not taking any advantage of the USI iterface or the spi in the case of the atmel 328p chip.

Hey SFE, what configuration is this? It looks like the constant voltage configuration, however the schematic in the spec sheet has the resistors on R/G/BOUT pins going to the LED with R/G/BFB going to ground - this is backwards from that. The constant current mode has resistors on both sides, which this breakout doesn’t have either. So, I’m curious.
Also baffling is the 27 Ohms resistors being used. Calculating numbers based on the spec sheet, the red channel ought to have a 100 Ohms and the green and blue 68 Ohms (based on 5V VCC pin on an Arduino). So, what gives?

Ok, Pearce responded (thanks Pearce!) The BoB is in constant current mode. From the datasheet, it shows 2 sets of resistors, RL and RXFB. The RL resistor is a load resistor and the engineer(s) said that’s optional.
As for the 27 Ohm resistors used, at the top of page 9 there’s a formula, Ixout = Vref/Rxfb where Vref is 0.6V. So a 27 Ohm resistor will set Iout to approximately 22.2mA.
There ya have it.

Page 13 of the Spec sheet says up to 6 meters at 2MHz. Not 100% on the I2C since a proper I2C device supports clock stretching, and I don’t think the WS2801 does. So it’s labeled as a 2-wire scheme, or interface device.

Greetings Sparkfunners,
congrats for all the good work you’ve been doing!
how about cooking for us a breakout board for something beefier, such as TI’s TLC5910? $5 per one RGB does not make sense in any decent RGB LED project, which may contain dozens of LEDs…
Thanks!

You probably want to move up to the TLC5911 (parallel, 80mA x16 channels) or the TLC5930 (serial, 40mA x12 channels). The TLC5910 is obsolete.
Mind you, there are others, however my search criteria was for active drivers with 1024 PWM steps driving between 40mA to 500mA. Change the PWM steps to a lower value and you get many other options.

Looking at the datasheet, the absolute maximum constant current for each LED is 30mA, but with 27Ω current limiting resistors I calculate ~100mA current. Can you explain this discrepancy? I believe it should be using 100Ω resistors instead.

total newb question - Could I drive 10 of these from an arduino pro using an external power supply (li-ion battery)?
Here’s what I"m thinking:
I see that the datasheet says it maxes out around 150mA. I know that the arduino maxes out at about 40mA per pin so I’m assuming I’d need an external power supply.
Could I use a lithium ion battery http://www.sparkfun.com/products/10500 and a 5V voltage regulator and hook up the positive terminal of the battery to the voltage (VCC) pin on these boards? How many amps (mA) can the li-ion battery supply? I know how to create a voltage regulator from this tutorial: http://www.sparkfun.com/tutorials/57
What is the best way to run these and the arduino pro at the same time with as light a battery as possible?
I am planning to attach these to a kite.
Thanks!

Man these things are bright. I bought 3 of them just to try them out and joined them together with some put through the holes and bent over on the ends just see how these work using the sample code. I like them. Too bad for me that they are so expensive. Great product though.
I think to make the connections more secure but still make it so each unit could be removed I could solder some right angle breakaway male headers to these units and hook them together with wires that have some kind of female end on the wires. Is there anything out there like this?

Hah i find these boards funny :) You guys are crazy. How do you sell the PCB with the stuff on it but dont sell the stuff?
Where can i buy these LEDs? I bought a strip from china and desoldered about 10 of them but that was some work heh.

It seems likely they probably used the 6-pin variant and snipped two of the pins off. http://www.sparkfun.com/products/9429
Failing that or needing more spacing then another good alternative would be 4-pin jumper wire. http://www.sparkfun.com/products/10364

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